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A recent research revealed that certain smartwatch bands contain perfluorohexanoic acid, a hazardous 'forever chemical' linked to potential health risks. However, not all watch bands contain these chemicals—so here's how to make informed choices when buying one.
What did the latest research uncover?
Before diving into watch band shopping details, let's understand the context. The study discovered that perfluorohexanoic acid and other PFAS were found in several of the tested watch bands. However, the researchers didn't examine the health effects on the individuals wearing the bands.
They examined 22 different watch bands from various brands and price ranges, discovering that 15 contained over 1% fluorine, indicating the presence of PFAS. This included all 13 bands marketed as being made with fluoroelastomers—something to keep in mind when shopping for a band.
The researchers successfully isolated a specific PFAS compound, perfluorohexanoic acid, from several bands. Other studies have suggested that this chemical may be absorbed through the skin, so it might be wise to avoid it until more is known about its health impacts.
How hazardous are PFAS in watch bands?
The short answer is: We don't have enough information yet. The Environmental Protection Agency’s fact sheet on PFAS outlines that exposure to “certain levels” of these chemicals has been linked to health issues such as decreased fertility, higher cancer risk, developmental delays in children, and a weakened immune system's response to vaccines, among others.
However, this is just a general overview of the research: Some studies have looked at extremely high levels of exposure (like those seen in people who work with large amounts of PFAS). Additionally, the PFAS family contains many different chemicals, some of which might be more harmful than others.
The EPA states: “Research is also underway to better understand the health effects associated with low levels of exposure to PFAS over long periods of time.” In short, we still don’t have enough information on the health risks of PFAS in watch bands, or in other environmental sources like water and soil. However, it may be a good idea to steer clear of bands with PFAS if you want to play it safe.
Graham Peaslee, the lead researcher on the watch band study, highlights that perfluorohexanoic acid, the specific PFAS compound the study focused on, has been under-researched. Until recently, scientists didn’t realize that it accumulates in the blood (it can be found in whole blood, but not in the serum typically sampled for these studies). More research on the health implications is expected in the future.
Which watch bands contain PFAS?
The study tested bands from Nike, Apple, and Fitbit, but it didn’t specify which brands or products tested positive for PFAS. Peaslee told me in an email, “We didn’t test enough samples to confirm that any one brand is completely PFAS-free or entirely PFAS-containing.” So, brand names aren’t a guarantee of safety.
What you can look for is the material listed for the watch band. Remember how all the fluoroelastomer bands in the study contained PFAS? Fluoroelastomer is a synthetic rubber often marketed as superior to silicone watch bands, which is why manufacturers proudly advertise these bands as being made from “fluoroelastomer” or “FKM” rubber. Peaslee advises: “If [a watch band’s description] mentions fluoroelastomer or FKM, avoid it. But if it says silicone, nylon, fabric, leather, or metal, then you’re PFAS-free.”
How do fluoroelastomer and silicone watch bands differ?
Silicone watch bands are not known or believed to contain PFAS. Fluoroelastomer bands, however, are more likely to contain PFAS, as indicated by the results of this recent study.
Fluoroelastomers are typically used in premium watch bands because they are more resistant to damage from sweat, oils, and chemicals. They have a smoother, less sticky texture compared to silicone bands. Many people prefer fluoroelastomers, and they tend to be more expensive than silicone options. Peaslee notes that if you're paying over $30 for a rubber-like band, it’s likely fluoroelastomer. (In the study, no bands under $15 tested positive for PFAS, which is one reason why being frugal can pay off.)
Fluoroelastomer bands are frequently marketed as “FKM rubber,” like this one that notes in the description: “FKM Rubber (Not Silicone).”
What should you consider when choosing a band for your smartwatch or fitness tracker?
Not all watch bands clearly state their materials; some of the bands in the study were not advertised as fluoroelastomer but still contained fluorine.
Based on this study and Peaslee’s guidance, the best way to avoid PFAS in a watch band is by looking for the following characteristics:
Not labeled as fluoroelastomer or FKM
Specifically labeled as being made from a different material, such as silicone, nylon, or leather
Inexpensive (ideally under $30, or better yet, under $15)
I asked Peaslee about “banned substances” lists that some manufacturers have published, like this one from Garmin and this one from Apple. He explained that since 2016, manufacturers have been working to eliminate PFOA and PFOS (two types of PFAS) from their products. However, there are many other PFAS chemicals, so the presence of such lists doesn’t guarantee that a brand is free from all PFAS.
Peaslee hopes that with enough consumer demand, brands will begin to market products as PFAS-free. But for now, the guidelines above are your best approach for finding a watch band that’s free from PFAS.
